As the need for energy continues to grow, so does the use of unconventional energy resources to meet the increasing demand. While well-known energy sources (e.g., coal, natural gas) continue to have value, other energy sources such as unconventional oil resources and unconventional natural gas resources are being used to meet the increasing energy demand. One such unconventional resource is sour gas, which is a natural gas that contains significant levels of hydrogen sulfide (H2S). H2S presents a problem during processing of the sour gas, as the corrosive nature of H2S can damage the mechanical parts of a system, and the processing of H2S can result in the production of SO2, which is an air pollutant.
Combustion is a commonly used reaction in the field of power generation and can be modified to use sour gas as fuel. However, combustion reactions, and specifically direct combustion reactions, still present the same corrosion and pollution issues associated with sour gas fuel. To avoid excessive corrosion and pollution associated with sour gas combustion, pretreatment or “sweetening” of the sour gas has been required to substantially remove the sulfur compounds from the gas stream. However, this “sweetening” process is typically very costly.
Chemical looping combustion (CLC), a specific type of combustion reaction, eliminates the need for a “sweetening” pre-treatment and can be used in a system for CO2 capture as well. In a conventional CLC process, an oxygen carrier acts as an intermediate transporter of oxygen between air and fuel, and thus the air and the fuel are prevented from directly contacting one another. Typically, a solid metal oxide oxygen carrier is used to oxidize the fuel stream in a fuel reactor. This results in the production of CO2 and H2O. The reduced form of the oxygen carrier is then transferred to the air reactor, where it is contacted with air, re-oxidized to its initial state, and then returned to the fuel reactor for further combustion reactions.
Despite their advantages over direct combustion processes, CLC processes are still inefficient in terms of their ability to produce energy. Additionally, CLC processes traditionally require coupling to steam cycles to produce power. Accordingly, there is a need for a cost-effective and energy-efficient system that combines the combustion of sour gas with power generation. Further, there is a need for a process for the combustion of sour gas with high efficiency in energy conversion, with reduced amount of water especially in water scarce environments.